Directive wireless system



Nov .9,1937. P, E'BANSK. Y 2,098,756.

DIRECTIVE WIRELESS SYSTEM Filed Nov. 2, 1934 s Sheets-Sheet 2 INVENTORIOZEF PLEBANSKI ATTORNEY Nov. 9, 1937. J. PLEBANSKI 2,098,756

DIRECTIVE WIRELESS SYSTEM Filed Nov. 2, 1934 5 Sheets-Sheet 5 AMPLIFIERRF. AMPLIFIER PHASE 5H IFIER RECEIVER iNVENTOR JOSE? PLEBANSKI ATTORNEYPatented Nov. 9, 1937 UNETED STAl'Eg FATE 'i GFE DIRECTIVE WIRELESSSYSTEM Application November 2, 1934, Serial No. 751,228 In PolandNovember 4, 1933 13 Claims.

This invention relates to antenna systems and more particularly todirectional receiving an tenna systems and has for its main object toprovide means whereby the directive properties 5 of a receiving antennasystem which is itself inherently directional may be substantiallyaugmented.

A further object of the invention is to provide improved means wherebythe direction of maximum sensitivity may easily and conveniently becontrolled.

These objects are achieved, in carrying out the present invention, bythe provision of what is V hereinafter referred to as directionalreaction. 15 This so-called directional reaction, as will be shownlater, increases the relative strength of signals arriving from thedesired direction as compared with signals arriving from otherdirections in a manner which is analogous to that 29 in which signals ofdesired. frequency are increased in strength relatively to those ofundesired frequency by ordinary reaction or regeneration in vacuum tuberadio circuits.

A further object of my invention is the prevision of means and methodsfor varying the de gree of sharpness of the transmitting and/orreceiving characteristic of a directive aerial system.

Another object of the invention is to provide a new directive system andmethod of operating 39 same by which a desired degree of sharpness ordirectivity is obtained with a substantially decreased amount ofapparatus required and with an aerial system of substantially reducedsize and extension as compared to directive aerial systems heretoforeknown in the art.

The invention has other objects and advantages in view which will appearhereinafter in a detailed description thereof in connection with theaccompanying drawings in which I have shown several forms of embodimentof the invention.

In these drawings:

Figures 1 and 2 illustrate schematically elevation and plan views,respectively, of one em- 45 bocliment of an aerial system according tothe invention.

Figures 3 and l show directive polar diagrams explanatory of thefunction and results of the system shown by Figs. 1 and 2.

50 figures 5 and 6 illustrate in elevation and plan views, respectively,a modification of an aerial system according to the invention.

Figures 7 and 8 represent vector diagrams explanatory of the function ofthe system accord- 55 ing to Figures 5 and 6.

Figure 9 shows a further directive aerial system of the type accordingto the invention, while Figures 10 to 13 represent descriptive polardiagrams explanatory of the function of and advantages obtained by theinvention. 5"

Figures 16 and 1'? illustrate more clearly the 10 arrangement of asystem according to the invention embodying superheterodyne amplifiersand phase shifting means for adjusting the di-' rectionalcharacteristic.

Similar reference characters identify similar parts throughout thedifferent views of the drawings.

Referring to Figures 1 and 2 which illustrate schematically elevationand plan views, respectively, of one embodiment of the invention, A1, 20A2 An represent a plurality of aerials such as straight wire aerials asshown, forming together with reflectors R1, R2 Rn, a directive an tennasystem of well known design. In order to obtain directional reaction inaccordance with the invention, a second directive antenna system HA1,HA2 RAH, together with reflectors RRl, RRz R31; is provided and eachindividual aerial RA1 or RAn of this auxiliary system is energized byoscillatory energy of suitable phase derived from the corresponding mainaerial A1 or An through feed line f1, f2 fn connected to the aerials bysuitable coupling means such as by inductance coils C and CR,respectively. The energy fed to the auxiliary aerials is amplified 5 byamplifiers Aml, AmZ Amp. which are inserted, as shown, in the feeders f1fn- Ihave furthermore shown a receiver RC of any known design connectedto the aerials A1 An such as through coupling coils C or by means of anyother coupling as may be desired.

In a system as above described, a radio signal incident upon the antennasystem A1 An is amplified in amplifiers Ami Amp. and is fed back byradiation from the auxiliary or reaction 5 antenna system RA1 RAH to themain antenna system A1 An as indicated by the arrows A in Figure l andin this way regeneration of the signal is obtained. Further, as will beseen from the following description, only signals coming from thedesired direction are regenerated.

Referring to Figure 3 which shows a polar receiving diagram of anantenna system according to Figures 1 and 2, the directionalcharacteristic of the main antenna and reaction antenna system are asindicated at A and B, respectively. In these characteristics the sectionfrom the points 0 or I to an inter-section point of the curve with aline drawn in a desired direction is proportional to the receiving fieldstrength of a signal arriving in this particular direction, as is wellknown. Then, assuming the same phase relationship or delay between thecurrents in each individual main aerial and the corresponding auxiliaryaerial, the said signal will be regenerated to the greatest extent,since if another signal on the same wave length is coming from anotherdirection II-O, then the directional characteristic C of the reactionantenna for tlr's signal is rotated by an angle 5 and this particularsignal is not regenerated or is regenerated to a much less extent. Thereason that the directional characteristic of the reaction antennasystem is now shifted is that the individual aerials RAi The relativephases are the same as those produced in the individual aerials A1 Allby the signal incident thereon at an angle at to the plane of theantenna system A1 An. In the system above described therefore, a signalcoming from the desired direction is regenerated and all signals comingfrom other directions are substantially not regenerated. In consequence,the overall directional characteristic of the system as a whole isgreatly improved as represented diagrammatically by the characteristic Baccording to Figure 4 as compared with the characteristic A withoutreaction.

The reaction of course can be made controllable and hence adjustment forany desired sharpness or degree of sensitivity obtained. Moreover, ifrelative phase shifts; that is, different time lags, are introduced inthe reaction feeders f1 fn, then the resultant direction of maximumsensitivity can be rotated, i. e. as indicated at C in Figure 4.

The provision of reaction in accordance with the invention has theadvantage that not only is the directional sensitivity greatly improvedbut the frequency selective properties, for the signal from a desireddirection only, are also improved and the desired signal enormouslyincreased in strength, the improvement compared with known directiveantenna systems being considerable.

A' system in accordance with the invention is moreover less expensivenot only from the point of view of initial cost but also from the pointof View of operation and maintenance. The main antenna system can beconstructed of fewer elements, the height can be reduced, the reactionantenna can be of a very small height (wires only three meters in lengthsuspended on cheap wooden poles have been successfully employed for thispurpose), the reaction feeders can be also small and inexpensive sincethe losses are largely covered by reaction, the main feeder leading tothe main receiver can be also less expensive since the large gain of thesystem will largely overcome the losses occurring therein, and thecomplication of using separate individual reaction amplifiers in theembodiment above described is largely oifset by the simplicity of themain receiver which can be used.

In the arrangement shown in Figures 1 and 2, a separate reactionamplifierAmi Amn is provided in each feeder connecting a main antennaelement with a corresponding reaction antenna element. Such anarrangement is however not essential unless it is desired to obtaincontrol o RAH are fed with phase shifted currents.

the direction of maximum sensitivity, and in the arrangement shown inFigures 5 and 6 showing a modification of the apparatus according toFigures 1 and 2 and explanatory vector diagrams as shown by Figures 7and 8, a single reaction amplifier Am is employed. In these figures A1An are the individual aerials which with the reflectors R1 Rn constitutethe main antenna system connected by means of a feeder line f to thereceiver RC. From any point of this feeder line, or from any convenientpoint in the circuit of the receiver RC, a tap M is connected to anamplifier or reaction adjusting device Am and from this point thereaction currents are transmitted over a feeder line I" to a singlereaction antenna RA, which may be directional or non-directional. Thereactive radiation traverses paths such as shown by the arrows a, b, ca: to the various antenna elements and if the signal is coming from thedesired direction the reaction currents in (Fig. 7) will be in phasewith the currents in, i132, in; and in in the example shown in thevarious individual aerials A1, A2 An; if the signal is coming from anyother direction, then the reaction currents in will not be in phase withthe currents in, irz, ir3 and "14 induced by the signal (Fig. 8) Insteadof the reaction antenna RA, reaction coils reacting upon every singleantenna A1 An may be used. However, a reaction antenna is moreconvenient and more easily constructed.

Another arrangement utilizing a non-directional reaction antenna isshown in the accompanying Figure 9 wherein FA1 and FA2 represent twoframe aerials spaced at a distance 11. Reaction energy from amplifiersAmi and AmZ is fed to two or, if desired, a single non-directionalantenna RAi and RAz which maybe one or two meters in height and situatednear together. For a signal coming from the direction I-O, the phases ofthe reactive antenna currents in RA1 and HA2 will be equal, but for anyother direction the phases will be shifted by an angle depending uponthe direction of the signal and spacing d. Any shifting of the currentsin RAi and HA2 means however areduction in the feed back energy reactingupon the frame aerials FAi and FAz.

Therefore the ordinary figure of eight characteristic of two framesseparated by a distance d which is small in comparison with the wavelength used will be drawn out and become something like that shown at Kin Figure 10 compared with the ordinary figure of eight diagram shown atK'.. A cardioid diagram for such an arrangement will be similarlyimproved as shown in Figure 11 in which K and K represent the diagramsfor the two cases; i. e. without and with radiation regeneration inaccordance with the invention. Instead of using reaction antennae RA1,RAz, reaction coils may be employed but in such case the coil or coilsfed from amplifier Aml must react upon both antennae FA1 and FA2, and inthe same way the coils fed from the other amplifier AmZ must react uponboth antennae.

Of course, the sharpening effect on the directional properties is morepronounced if both the main antenna and the reaction antenna aredirectional. It is desirable to choose very sharp directionalcharacteristics for the reaction antenna but these need not beuni-directional. For instance, characteristics as shown in theaccompanying Figure 12 or 13 can be used with good results.

The reaction amplifiers employed may comprise any desired number ofstages which may be tuned or aperiodic but for good results it isessential that the amplification be linear so far as is possible. Thiscondition is not difficult to attain if the grid swing on the amplifierbe kept small. The degree of amplification necessary depends naturallyupon the distance of the reaction antenna from the main antenna and uponthe losses occurring in the feeders. If a large degree of amplificationis necessary, the superheterodyne principle may be used and theintermediate frequency must then be changed again to the originalfrequency. This can be easily done by means of a single local oscillatorfor all amplifiers. The intermediate frequency heterodyned with thelocal oscillator frequency will yield the original radio frequency sincen0nh+nh=no is the original signal frequency and m is the heterodynefrequency and -121; is the intermediate frequency. Such a system is veryconvenient because by adjusting the heterodyne output applied to thevarious reaction circuits the degree of reaction can be controlledeasily and simultaneously for all the circuits.

Furthermore, by using a single heterodyne oscillator and adjusting thephases of the heterodyne oscillations applied to the various circuits,the rotational adjustment of the direction of maximum sensitivity mayeasily be performed. If the superheterodyne principle be not used foradjustment of reaction the output of all amplifiers Aml Amn may be madeadjustable in any known manner, e. g. by means of potentiometers,variable coupling systems, variation of the potential of the screengrids, variable mu valves, etc., and naturally for convenience it ispreferable to couple mechanically or synchronize in any known manner theindividual adjustments of each amplifier. The adjustment of the outputsof all amplifiers Aml Amn must of course be equal in order to obtain inevery case equal currents in all the individual aerials of the reactionantenna.

In order to rotate the over-all beam characteristic it is necessary, aspointed out, to provide additional phase shifts in the reaction feeders,for instance, with the following phase relationship: feeder f1phase 1:0,feeder fzphase 21, feeder f3phase 3=2, feeder fnphase One method ofefiecting this phase shift is by adjusting the lengths of the individualfeeders. If it is desired to make this adjustment uni-controlled it ispreferred to employ the superheterodyne principle as previouslydescribed since otherwise unicontrol, although not impossible, isdifficult of achievement in practice.

The reaction amplifiers can be mounted in a hut between the main antennaand the reaction antenna or as shown in Figures 14 and 15 in the mainreceiving building. In this latter case from each unit antenna A1, A2,A3, A4, individual feeders f1, f2, f3, f4 transmit the currents to thereaction amplifiers Aral, Am2, Am3, Ami. From the output terminals ofeach amplifier a feeder f1, f2, f3, f4 transmits the reaction currentsto one unit of reaction antenna RAi, RAz, HA3, RAi. From the input sideof the amplifiers the feeders are combined and transmit the currents tothe receiver RC. On the heterodyne unit indicated diagrammatically at H,two controls may be 3.1? ranged, control N for controlling of thereaction which may consist of a variable coupling for all the first andpossibly for the second detectors or means for varying the bias forvariable-mu valves, and the other control Pfor controlling or rotationof the whole beam characteristic, such as by means of ganged condensers.

A system of the above mentioned type is more clearly shown in Figures 16and 17 which in general correspond to the arrangement as shown inFigures 1 and 2 with the exception of the provision of superheterodyneamplifiers and phase shifting means for adjusting the directionalcharacteristic. The amplifiers shown comprise first or input mixerstages HA1 HAn supplied from a common local oscillator shown at 0. Themixing of the input frequency currents with the local frequency currentsupplied by the oscillator 0 may be carried out in accordance with anyone of the known methods such as by means of specially designed electrontubes known as electronic mixers. The intermediate frequency currentsobtained from the output of the first mixer stages are then amplified inthe usual manner by means of intermediate frequency amplifiers shown atIA1 IAn. After amplification at intermediate frequency the signals areagain returned to their original frequency in accordance with theinvention by means of second frequency changing or mixer stages shown atHA1. HAn' wherein the same local oscillator shown at 0 may be used tosupply the mixing or heterodyning current in such a manner as to obtainthe original signal frequency by beating of the intermediate frequencycurrents with the local frequency currents supplied by the oscillator O.I have shown further high frequency amplifying stages HA1". HAn" forincreasing the amplitude of the restored signal which directly feed intothe reaction antennae RA1 R-An in a manner similar as described in thepreceding figures. Items P1 Pr), represent phase shifters such asvariable condensers in the supply leads 'from the local oscillator O tothe second mixer stages preferably provided with a common control means,indicated at K, such as is customary with gang condensers forsimultaneously adjusting the output phases for varying the direction ofthe receiving characteristic of the entire systern in a manner asdescribed hereinbefore.

The invention is of course not limited to the arrangements described andshown in the accompanying figures. Various other combinations arepossible provided that in the main aerial spaced unit antennae are usedfrom which various phases are fed through one or more amplifiers to thereaction system. The reaction system can be constituted by a directiveor non-directional aerial or else reaction coils as previouslydescribed.

It is important of course for the good working of the system to have asmooth reaction control. This can be obtained in any known manner, forexample, by the use of leaky grid detector valves as special reactionvalves whose output may be amplified if necessary. By pushing reactionnear to its critical value, just before oscillations occur, exceedinglysharp directive characteristics can be obtained in a manner which isanalogous to the high frequency selectivity obtainable in the knownfrequency reaction circuits. In this manner, the beam may be confinedwithin an angle of a half degree.

In the foregoing description improvements of the directionalcharacteristics in the horizontal plane only have been considered. It ishowever also possible, according to the invention, to improve thevertical characteristics. For this purpose a reaction antenna may beused in which standing the reaction beam is caused to swing in thevertical plane.

Itwill be seen from the above description of my'invention that thedirectional selectivity or degree of sharpness of a direotivewireless.an-

tenna system is considerably increased by the @may be made withoutdeparting from the spirit and scope of the claims appended hereto.

I claim:

A directional system comprising a directional receiving antennahavingits line of maximum receptivity pointing in the direction of .thetransmitter being received, means for amplitying signals received bysaid antenna, and an auxiliary antenna connected to said amplifyingmeans and located substantially on a line joining the receiver andthetransmitter for. radiating a portion of the amplified received signals,vwhereby signals incident upon the system from the transmitter aredifferentially accentuated by regenerative radiation from said auxiliaryI ant nn 7 2. A systemv as claimed in claim 1 including phase shiftingmeans between said amplifying means and said auxiliary antenna.

3. A system as claimed in claim. l in which i said auxiliary antenna isa non-directional antenna a l 4. A systemas 'claimedinclairn .l in whichsaid auxiliary antenna is a directional antenna having its direction ofmaximum radiation in line with the direction of maximum receptivity ofsaid receiving antenna.

5. Adirectional receiving system comprising a plurality of antennaelements adapted to ab sorb incident electromagnetic wave energy atdifferent phase angles dependent on the direction of incidence of theenergy being received, means for combining the energies received by saidantenna elements for directive reception, a reaction antenna arranged ata predetermined relative location to said antenna elements, circuitconnections between said antenna elements and said reaction antenna,means included in said circuit connections for adjusting the phase ofthe energy fed to said reaction antenna, and further means included insaid circuit connections for changing the frequency of the reactingenergy derived from said antenna elements to intermediate frequencyenergy, amplifying the intermediate frequency energy and changing thefrequency back to the original frequency before application to saidreaction antenna.

6. A directional receiving system comprising a plurality of antennaelements adapted to absorb incident electromagnetic wave energy atdifferent phase angles dependent on the direction of incidence of theenergy being received, means for combining the separately receivedenergies for directive reception, a reaction antenna arranged at apredetermined relative location to said antenna elements, circuitconnections between said antenna elements and said reaction antenna,means included in said circuit connections for adjusting the phase ofthe reacting energy fed to said reaction antenna, and

further means including a single local oscillator for heterodyning thefrequency of the reacting energy to'intermediate frequency energy,amplie fying the intermediate frequency energy and I heterodyning theamplified energy to restore the original frequency before application tosaid re,- action antenna.

7. A directional receiving antenna system comprising a plurality ofspaced antenna elements, means for combining the energy picked up bysaid elements in the required phase relationship for directivereception, means for amplifying the combined energy and means forradiating a portion or the amplified energy. from a point lyingsubstantially in a line joining the receiver and the transmitter whosesignals are to be received whereby signals incident upon the system fromsaid transmitter are differentially accentuated by regenerative actionby said radiation.

8; Av directional antenna system comprising a plurality of spacedantenna elements*'-' constituting a main directionalreceiving antenna, afurther corresponding plurality of spaced antenna elements constitutingan auxil iary directive antenna, means for separately amplifying 'energypicked up by individual main antenna elements, and means for feedingsaid separately amplified energies individually to cor-. respondingelements of I said auxiliary antenna whereby said auxiliary antenna iscaused to radiate energy differentially reacting upon the elements ofsaidmain antenna in such a manner as to accentuate signals incidentuponsaid main antenna from a predetermined direction.

9. A directional antenna system comprising a plurality of spaced antennaelements constituting a main directional receiving antenna, a furthercorresponding plurality of spaced antenna elements constituting anauxiliary directive antenna, means for separately amplifying energypicked up by individual main antenna elements, means for feeding saidseparately amplified energies individually to corresponding elements ofsaid auxiliary antenna whereby said auxiliary antenna is caused toradiate energy in such manner differentially reacting upon said mainantenna elements so as to accentuate signals incident upon said mainantenna from a predetermined direction, and means for introducing anadjustable relative phase shift between the reacting energies derivedfrom individual antenna elements whereby the direction of maximumsensitivity of the system may be adjusted.

10. A directional antenna system comprising a plurality of spacedantenna elements consti tuting a main directional receiving antenna, afurther corresponding plurality of spaced antenna elements constitutingan auxiliary directive antenna, means for separately amplifying energypicked up by individual main antenna elements, means for feeding theseparately amplified energies individually to corresponding elements ofsaid auxiliary antenna whereby said auxiliary antenna is caused toradiate energy differentially reacting upon said main antenna elementsin such manner as to accentuate signals incident upon said main antennafrom a predetermined direction, and means for introducing an adjustablerelative phase shift between the reacting energies derived fromindividual antenna elements whereby the direction of maximum sensitivityof the system may be adjusted, the energy for reaction being heterodynedto and amplified at an intermediate frequency and then again heterodynedto the original frequency before application as reacting energy.

11. A directional antenna system comprising a plurality of spacedantenna elements constituting a main directional receiving antenna, afurther corresponding plurality of spaced antenna elements constitutingan auxiliary directive antenna, means for separately amplifying energypicked up by individual main antenna elements, means for feeding theseparately amplified energies individually to corresponding elements ofsaid auxiliary antenna whereby said auxiliary antenna is caused toradiate energy differentially reacting upon said main antenna elementsin such manner as to accentuate signals incident upon said main antennafrom a predetermined direction, and means for introducing an adjustablerelative phase shift between the reacting energies derived fromindividual antenna elements whereby the direction of maximum sensitivityof the system may be adjusted, said first means comprising a singlelocal oscillator for heterodyning the energy for reaction to anintermediate frequency, amplifying and heterodyning the intermediatefrequency energy to the original frequency before application asreacting energy.

12. A directional antenna system comprising a plurality of spacedantenna elements comprising a main directional receiving antenna, afurther corresponding plurality of spaced antenna elements constitutingan auxiliary directive an,

tenna, means for separately amplifying energy picked up by individualmain antenna elements, means for feeding said separately amplifiedenergies individually to corresponding elements of said auxiliaryantenna whereby said auxiliary antenna is caused to radiate energydifferentially reacting upon said main antenna elements in such manneras to accentuate signals incident upon said main antenna from apredetermined direction, said first means comprising a single localoscillator for heterodyning, the energy for reaction to an intermediatefrequency amplify-l ing and heterodyning the intermediate frequencyenergy to the original frequency before application as reacting energy,and means for adjusting the phase of the local oscillation produced bysaid oscillator.

13. A directional receiving antenna system comprising a plurality ofspaced antenna elements reflector elements being associated with saidspaced antenna elements, means for combining the energy picked up bysaid elements in the required phase relationship for directivereception, means for amplifying the combined energy and means forradiating a portion of the amplified energy from a point lyingsubstantially in a line joining the receiver and the transmitter whosesignals are to be received to produce a differential regeneration uponsaid antenna elements whereby signals incident upon the system from saidtransmitter are accentuated by regenerative action by said radiation.

J OZEF PLEBAN SKI.

